Since the amount of interferon in biological fluids is very low, one goal was to produce human lymphoblastoid interferon in large quantities. The cell line Namalva was induced with Newcastle disease virus, strain Bl. The growth of Namalva cells to volumes of 200 liters was accomplished using the pilot plant facilities (NIAMDD) Bldg. 6 under the supervision of Mr. David Rogerson. Subsequently interferon was produced by dilution of virus induced cultures with serum-free medium to final volumes of up to 800 liters. These preparations have yielded approximately 5-10 mg lymphoblastoid interferon. Studies examining the growth of Namalva cells in serum-free medium are also in progress. It was found that these cells were capable of growing in at least one serum-free medium. Methods for the purification of lymphoblastoid interferon from the crude tissue culture fluids include trichloroacetic acid precipitation, immunoabsorbant-affinity chromatography, gel filtration, isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Lymphoblastoid interferon has been partially purified to at least 3 x 10 to the 8th power units/mg. Experiments are now in progress to use all of these methods to achieve a homogeneous preparation of interferon.